Receptor-type tyrosine-protein phosphatase C (CD45RA) (CD45RA)

Receptor-type tyrosine-protein phosphatase C (CD45RA) is a specific high-molecular-weight isoform of the CD45 antigen, encoded by the PTPRC gene. It is characterized by the presence of the "A" exon and is predominantly expressed on the surface of naïve T lymphocytes, as well as some B cell and NK cell subsets [UniProt: P08575]. CD45RA functions as a critical regulator of T-cell activation by modulating the phosphorylation state of Src-family kinases, such as Lck and Fyn, thereby initiating the T-cell receptor signaling cascade [PubMed: 21637290]. In clinical medicine, CD45RA+ naïve T cells are recognized as the primary mediators of graft-versus-host disease (GvHD) following allogeneic hematopoietic stem cell transplantation [PubMed: 24925918]. Because these cells are highly alloreactive, their selective depletion from donor grafts is a therapeutic strategy to reduce GvHD while maintaining the protective immunity provided by CD45RO+ memory T cells [PubMed: 25352123]. Therapeutic interventions targeting CD45RA include monoclonal antibodies and specialized cell-processing technologies like the Orca-T platform [ClinicalTrials.gov: NCT04013685]. This target is also relevant in autoimmune research and the study of immune system aging, where the ratio of CD45RA+ to CD45RO+ cells serves as a key biomarker [PubMed: 15634491]. Overall, CD45RA serves as both a critical biological regulator of immune activation and a vital target for engineering safer cellular therapies.

Other names

PTPRCLeukocyte common antigenLCAT200CD45 isoform RACD45RA

Selective depletion of CD45RA-positive naïve T cells to prevent graft-versus-host disease while preserving memory T-cell immunity for anti-pathogen and anti-tumor responses.